When works of art on paper

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					preservation practices

                                     Improving the Pass-Through Hinge
                                       hen works of art on paper      their frames in museums and other
                                       are secured with Japanese      public collections, the pass-through
                                       tissue and paste hinges, the   hinge presents a problem in that the
                        hinges must be applied by skilled per-        hinge is exposed on the back of the
                        sonnel who are versed in appropriate          back mat and can be disturbed as the
                         application and drying techniques.           mat is moved about. If the work is per-
                                Even well-applied hinges may          manently stored in a frame, however,
                                    not operate successfully if       passing the image through has benefits.
                                      they are secured too tightly          It reduces the time needed for dry-
                                       to the back mat. A hinge       ing since the hinge can be secured to
                                        firmly pasted to the back     the back of the back mat with gummed
                                        mat will fix the art to the   tape in place of the usual paste attach-
                                        board at that point and,      ment to the front side of the back mat.
                                       during changes in relative     The passage of the hinge through the
                                      humidity, the paper may         slit in the back mat also allows a mod-
                                    expand more rapidly and           icum of lateral movement for the hinge
                                extensively than the board can.       along the length of the slit. This can be
                               Customers who expect that their        useful in addressing the problem of
                        work should remain perfectly flat will        overly intimate bonding between the
                        obviously be upset if it cockles at its       art and the back mat.
                        edges between the hinges. In addition,              The design of the slit is critical. To
                        they may not be satisfied with an             ensure that the hinge is not locked up
                        explanation of the risk to the value of       by friction with the fibers of the board
                        their work which overall mounting             as it passes through, it has been recom-
                        poses. Thus, it is important to engineer      mended that the slits be cut with a
                        the attachment of the hinge to the back       bevel, not perpendicular to the plane of
                        mat so that the art is supported gently       the board. The beveled cut also makes
                        and steadily without too intimate a           insertion of the hinge through the
                        bond.                                         board much easier.
                             One method of attachment which                 When the beveled slit is made it
                        is used more frequently in shops than it      should be cut so that its top side will be
                        is in institutions is the pass-through        just behind the edge of the art and it
                        hinge. Since works are stored outside         will angle out and back, away from the

70 PFM   i April 1998
  preservation practices

     Figure 1

edge of the art. The hinges should have been situated so           passed through with paper sleeves, as before, and secured
that their adhesion to the art ends just shy of the outer          with gummed paper or linen tape (figure 1).
edge of the art. Thus, when the hinge is passed through,                This more elaborate pass-through slit diminishes the
the slit will be under the edge of the art and will not be         mass of the board at the point at which the hinge transits
able to engage the art’s edge if there is any warpage. Direct-     and creates a more physically sympathetic setting. It is
ing the cuts out from the edges of the art, rather than in         important to make the cuts carefully so that they do not
behind them, means that the hinges operate as if they were         create an unsightly opening in the front of the back mat
pendant hinges rather than folded hinges and reduces the           which might show under the edge of translucent papers.
effects of friction. All of these issues, plus the use of folded        This is yet another advantage to this method. If a
paper insertion sleeves, have been explored previously             work were to be removed from a back mat through
(PFM Preservation Supplement, February 1994).                      which hinges had been passed using prior techniques, the
      As well as such techniques may work, they can be             unthreading of the hinges from the slits could be difficult
improved. Central to the successful practice of preserva-          and hazardous to the hinges and, ultimately, to the edges
tion framing is the commitment to the improvement and              of the art. “Teasing” the hinges back through the slits
refinement of its materials and techniques. Changes are            often results in torn or dislodged hinges. The bending of
never made for their own sake, but rather in response to           the back mat required to open the slits is also potentially
weaknesses in current methods. If these ordinary slits are         dangerous to the art. The inverted V-shaped slit lends
used to pass through light weight hinges on a delicate             itself to easy rethreading of hinges back through the back
sheet of paper, it is easy to see that they still offer too        mat and enhances safe removal of the art.
much friction and too strong a hold for such fragile                    Next month we will look at an improvement for
material. This is not a minor issue, since the pass-               cross pieces used with folded hinges to further this
through hinge is most useful with light weight papers              inquiry into the possibilities for gentle, steady support of
since they are often translucent. The attachment of the            works which must be housed and displayed so that their
hinge to the front of the back mat would therefore show            edges are exposed. s
through the art.
      What is called for is a redesign of the slit which reduces
the mass of the board where the hinge passes through and
allows for the more gentle operation of the hinge.
      One method of achieving this employs two slits cut
into the back mat at the same place but with opposing
bevel angles. This is essentially an inverted V-groove. The
slit should be situated exactly as before (just beneath the
edge of the art). The slits can now be cut with a cutter or
by hand using a straightedge, depending on the skill of
the craftsperson. There will be a V-shaped strip of board
which will be partially released from the back of the back
mat by the cutting. This strip can be trimmed out as its
ends and the slit will be complete. The hinges can be

72 PFM   i April 1998

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